Controlled chilling of precision metal parts



March 19, 1946.

W. L. CARSON CONTROLLED CHILLING OF PRECISION METAL PARTS Filed June29,-1942 2 Sheets-Sheet 1 INVENTOR. W1/// am 012? 0/: BY

Match 19,1946. w. L. cAasobl CONTROLLED CHILLING OF PRECISION METALPARTS Filed June 29, 1942 2 Sheets-Sheet 2 Patented Mar. 19, 1946CONTROLLED CHILLIN 'G F PRECISION METAL PARTS William L.' Carson,Seattle,"Wasli'., assignor to Washington Iron Works, Seattle, Wash, acorporation of Washington 1 Application June 29, 194.2,Seiial No.449,034

'6 Claims. (Cl. 266-:6)

'Thisinvention relates to the production of precision metalpartsrequiring surface hardness, and resides in the novel treatment ofthe part which, after being forged or otherwise formed to shape, isfirst rough-machined, then heated and,

subjected to a rapid chill while restrained against distortion, andfinally given a finish grinding.

.The invention resides further in a perfected mold or die foraccomplishing the chilling step,

Looking, therefore, to a treatment of metal forgings requiring precisionsurfaces and which will permit largeescale production, the inventionconsists in the perfected process and in the construction, adaptationand combination of parts embodied in a novel mold characterized by aclamping function and which operates to carry the essential chillingstep of the treatment into effect, all of which will be hereinafterfully described and claimed.

) In the accompanying drawings:

Figure l isa side elevational view of a chilling mold constructed inaccordance with the preferred embodiment of the present invention, andshowing fragmentaril the supporting-standards for themachine frame, thewater-circulating and air-supply lines, and the operating bar whichtransmits clamping pressure to a work-piece received within the mold.

Fig. 2 is a transverse vertical section thereof taken to an enlargedscale on line 2-2 of Fig. l; and r a Fig. 3 is a transverse verticalsection showing the mold in open position. g

It will of-course ,be'understood that the invention is inno" senselimited to any specific design of work-piece, and that a functionalcounterpart of the machine illustrated in the drawings could, withoutinvention, be readily engineered to accommodate' adiiferently designedmetal part, By way of exemplifying a precision part which lends itselfto a fast-chilling within a mold embodying the teachings of the presentinvention, 1 have selected a work-piece'as indicated by the letter W andwhich is produced to a T-form considered in transverse vertical sectionand has a quadrantal configuration in side elevation. This particularwork-piece is one which finds usage as a track-wa in the construction ofbomber planes with the track being described by the two facing surfaceswhich lie at opposite sides of the T wings.

There is no novelt inherent to performing,

upon a part which has been formed to shape.

the initial step of rough-machining and then heating the part followedby a subjection of the same to. a chill operation, with a finalfinishgrinding of the precision surface or surfaces. Thetreatment of aprecision part by this process has been long practiced, andsubstantially the only objection to the operation has been the extendedperiod of time required in bringing the heated part toatmospherictemperature for the final precision-grinding, this from thefact that a slow chilling has been deemed necessary to precludedistortion. It can be readily appreciated that this objection wouldbenormally of far less import than it is during the present emergency, butit now becomes a matter of necessity to expeditejthe, productionschedule on. any part used in the war effort. The present inventionaccomplishes the very desirable end of appreciably reducing the periodof time required for the distortion-free production'of such a precisionpart as I have de'scribedand it is in the chilling step that the timesaving'is attained,

Describing, therefore, the structure which I have illustrated forvperforming this fast-chilling of a precision part, there is provided amold assembly as well termed a die-comprised of a foundation block 3complemented by paired clamping jaws 4 and 5, the block being stationaryand functioning as the floor or bottom wall of a mold cavity of whichthe clamping jaws act as the top and sides. Such cavity corresponds inshape to the wing principals a and b of the workpiece, these being theparts whose surfaces are to be precision-ground, and there is provided alongitudinally extending median slotin the top wall of the molddefinedbetween the two jaws-'- whichaccommodates the projection therethrough ofthe web element 0 of the work-piece.

The said jaws, for lateral swinging movements into and fromwork-clamping positions, are each an integral part of a respective cheekplate, as 6 and i, which lie at opposite sides of the foundation block,and each such plate finds a hinge mounting upon a related hinge pin,as.8 and 9, which ex tends longitu'dinally of the foundation block andis supported by mounting lugs to and l I, re-

and provide outer extensions for engagement with the related hinge pin,while connecting by inner extensions with drop-links I4 and I5 which inturn connect with actuating cross-arms l6 fixedly supported upon alongitudinal operating bar I! reciprocally operated through a verticalpath of movement from a suitable source of power, the travel of the barin itsmold-opening movement being suflicient to retract the jawslaterally beyond the side limits of the foundation block for permittinga straight-draw feed of the work-pieces into and from the mold cavity.Salient to both the foundation block andthe clamping jaws is a cavitaryconstructionthereof to describe water-jackets as indicated at 21 2t and22, and each said jacket is tapped at the two ends for the reception ofnipples or other suitable fittings accommodating water-circulating pipes23-24 to and from the stationary block, and flexible hoses 25-46 to andfrom the movable jaws. There is additionally provided upon each of themovable jaws a pipe 21 having connection through a flexible hose 28 witha pressure source of cooling air, and formed in such pipes 21 areforamina 21" through which the pressure air is discharged in amultiplicity of jets over; the surfaces of the protruding web c of thework-piece. In closing the jaws 4 and 5 upon a work-piece which has beenintroduced over the floor-formmg block 3 of the mold, it is necessarythat the jaws be caused to bear firmly upon the upper faces of. theprecision wings a and b throughout the surface which is to beprecision-ground, and I accomplish this end by converting the swingingtravel of the jaws to a rectilineal action at the inner extreme of thejaws closing movement. It is topermit this action that the hinge pins,at their points of connection with the crossarms I2 and [3, arepermitted to spring slightlyfrom. axial prolongations of the bearinglugs l0 and l I, respectively. The complete process including thefast-chilling of the precision part by the instrumentality of clampingthe same securely within a. waterjacketed mold formed substantially incorrespondence with the said part is thought to be 7 clear fromtheforegoing. The rapidity with which. the water jackets acting incomplement with the air manifolds radiate the heat from the clamped partpermits. the latter to be ejected chilled to the required atmosphericworking temperature at which the required final step ofprecision-grinding may be performed-at intervals of minutes.'

It is intended that no limitations be implied, and that the heretoannexed claims be read with only such restrictions as are necessarilyintroduced thereto to distinguish from prior knowledge in the art.

What I claim is:

1-. In the art of fast-chilling a heated metal part: aclamping diecomprising. the combination of heat-conductive stationary and movablejaws acting in complement to describe a mold cavity for the part and.each water-jacketed for accelerating the dissipation of heat from thesame; water-circulating connections to and from the jacketing of therespective jaws; and devices functional to the movable jaws for swingingthe same into mold-closing positions and operating at the inner extremeof the closing travel to convert the swinging to a rectilineal clampingpressure applied in a direction substantially at right angles to thesurface being clamped.

2. A clamping die according to claim 1 for use in chilling a metal parthaving both precision and non-precision surfaces of which the precisionsurfaces are clamped by the die to restrain the same against distortion,and the non-precision surfaces exposed, the die providing foraminatedair manifolds having connection with a pressure source of cooling airand functioning to discharge jets of cooling air over the exposednon-precision surfaces of the part being chilled.

3. In the art of fast-chilling a heated metal part: a clampingdiecomprising the combination of heat-conductive stationary and movablejaws acting in complement to describe a mold cavity for the part; anddevices functional to the movable jaws for swinging the same into andout of moldcl'osing position and operating at the inner extreme of theclosing travel to convert the swinging to a bodily rectilineal movementexerting clamping pressure in a direction substantially at right anglesto the surface being clamped.

4. In the art of fast-chilling a heated metal part: a clamping diecomprising the combination of complementary jaws arranged to be openedand closed and acting in complement to describe a mold cavity for thepart; and devices functional to saidljaws for swinging the same into andout of mold-closing position and operating at the inner extreme of theclosing travel to convert the swinging to a bodily rectilineal movementexerting clamping pressure applied in a direction substantially at rightangles to the surfaces being. clamped.

5; A die for clamping a production part and comprising, in combination:a movable jaw acting as one element of the clamping structure; and meansfunctional to the jaw for swinging the same into and out of a positionwhereat the same closes upon the part to be clamped and operating at theinner extreme of the closing travel to convert the swinging movement ofthe jaw to a bodily rectilineal movement.

' surface being clamped.

6. A die for clamping a production part and comprising, in combination:a stationary jaw;

- WIILIAM L. CARSON.

